6 Best Free Online ASN to IP Lookup Websites

Here is a list of best free online ASN to IP lookup websites. ASN or Autonomous System Number is a type of unique identifier assigned to an Autonomous System or AS on the Internet. The main purpose of ASN is to route and traffic exchange on the internet. Many other internet infrastructures use ASN for different purposes like BGP Routing, Peering Agreements, Traffic Engineering, etc. At times, it is necessary to perform ASN to IP lookup to obtain all the IP addresses associated with a specific ASN value. If you also want to do that, then check ASN to IP lookup websites.

These websites use ASN numbers as input and look up all the IP addresses associated with them. Some of these websites can also obtain additional data through ASN values like IPv4 Prefixes Announced, IPv4 Bogon Prefixes, AS Name, etc. After obtaining the final result, users can easily copy and locally save the resultant values. To help out users, I have included the necessary lookup steps in the description of each website. On these websites, users can also find additional online tools like MXLookup, DNS Lookup, DMARC Lookup, and more. Go through the list to know more about these websites.

My Favorite Online ASN to IP Lookup Websites:

hackertarget.com is my favorite website as it can perform batch ASN to IP lookup operations. Plus, it shows all the IP addresses associated with a given ASN.

You can also check out lists of best free Online VIN Lookup, Online DS Lookup, and Online SOA Lookup websites.

Comparison Table:

Features/Website Names	Shows all the associated IP Addreses	Supportan batch ASN to IP lookup operations	Shows additional details associated with an ASN
hackertarget.com	✓	✓	x
mxtoolbox.com	✓	x	✓
ipinfo.io	✓	x	✓
traceroute-online.com	✓	x	x
asnlookup.com	✓	x	✓
bigdatacloud.com	x	x	✓

hackertarget.com

hackertarget.com is a free online ASN to IP lookup website. This website offers an Autonomous System Lookup tool that can perform ASN, AS, and IP lookup operations. For input ASN values, it also shows their corresponding IP values. It also supports batch ASN to IP operations as it supports batch lookup. After performing the lookup, it shows a range of IP values that users can copy. Now, follow the below steps.

How to perform ASN to IP lookup online using harckertarget.com:

Go to this website and access the Autonomous System Lookup section.
After that, enter one or more ASN values in the input field.
Next, click on the Lookup ASN button to start the lookup process.
Finally, view all the corresponding AS or IP addresses.

Additional Features:

This website also offers useful online tools like TCP Port Scan, UDP Port Scan, Subnet Lookup, Banner Grabbing, and more.

Final Thoughts:

It is one of the best free good online ASN to IP lookup websites that can also perform batch ASN to IP lookup operations.

Pros	Cons
Supports batch ASN to IP lookup operations

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mxtoolbox.com

mxtoolbox.com is a free online ASN to IP lookup website. Using this website, users can look up IP addresses using Autonomous System Number. It also shows the total amount of IPs along with AS Number, AS Name, and CIDR range. Besides this, a good set of additional lookup tools are also provided by it. Now, follow the below steps.

How to perform ASN to IP lookup online using mxtoolbo.com:

Start this website using the given link.
After that, enter the ASN code in the input field.
Next, click on the ASN Lookup button to view the corresponding IP addresses.

Additional Features:

This website also comes with additional tools like MXLookup, DNS Lookup, DMARC Lookup, Email Health, LOC Lookup, and more,

Final Thoughts:

It is a good online ASN to IP lookup website that shows the total number of IPs for a specific ASN along with AS Name, AS Number, and CIDR Range.

Pros	Cons
Shows the total number of IPs or a specific ASN

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ipinfo.io

ipinfo.io is another free online ASN to IP lookup website. Through this website, users can quickly lookup for IP addresses associated with an ASN value. Besides this, it also shows the website name, number of IPs, ASN Type, WHOIS Information, Hosted Domains, Peers, Upsteams, and Downstream information associated with an ASN value. Now, follow the below steps.

How to perform ASN to IP lookup operation online using ipinfo.io:

Go to this website and enter one ASN value in the input field.
Next, press Enter button to view the lookup process.
Finally, view IP address Ranges corresponding to a given ASN value.

Additional Features:

This website also offers additional tools like IP to Geolocation API, IP to Company API, ASN API, Contact API, etc.

Final Thoughts:

It is another good online ASN to IP lookup website that also shows WHOIS, Peers, and Hosted Domains related to an ASN.

Pros	Cons
Also shows WHOIS, Peers, and Hosted Domains data related to an ASN

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traceroute-online.com

traceroute-online.com is another free online ASN to IP lookup website. Through this website, users can obtain all the associated IP addresses with an Autonomous System Number (ASN). Besides ASN value, users can also enter IP Address and String value to perform the lookup process. Now, follow the below steps.

How to perform ASN to IP lookup operation online using traceroute-online.com:

Go to this website and access the IP to ASN Lookup tool.
After that, enter the ASN value in the input field.
Next, click on the Lookup! button to view all the associated IP addresses.

Additional Features:

This website also offers additional Check DNS, mtr online traceroute, and Internet Maps tools.

Final Thoughts:

It is another capable online ASN to IP lookup website that helps users find IP addresses associated with an ASN.

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asnlookup.com

asnlookup.com is another free online ASN to IP lookup website. It is another good website to perform ASN to OP lookup operations. It can also use IPv4, IPv6, and registered IP addresses to perform ASN lookup. Using the ASN value, it shows all the IPv4 CIDRs addresses, regional registries, countries, organizational names, organizational IDs, and more. Now, check out the below steps.

How to perform ASN to IP lookup operation online using asnlookup.com:

Go to this website using the given link.
After that, enter the ASN value in the input field.
Finally, click on Lookup! button to view all IP addresses and other associated information.

Final Thoughts:

It is another simple and effective online ASN to IP lookup website that anyone can use with ease.

Pros	Cons
It can also use IPv4, IPv6, and IP addresses to perform ASN lookup

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bigdatacloud.com

bigdatacloud.com is another free online ASN to IP lookup website. Through this website, users can also look up ASN data like IPv4 Prefixes Announced, IPv4 Bogon Prefixes, AS Name, and range of IP addresses of both IPv4 and IPv6 types. It even shows the range of a specific ASN and associated IP addresses over a world map. Now, follow the below steps.

How to perform ASN to IP lookup operation online using bigdatacloud.com:

Go to this website and open up the ASN lookup tool.
After that, enter the ASN value in the input field.
Next, click on the Lookup button to start the ASN to IP lookup operation.
Finally, view the obtained IP addresses and other details.

Additional Features:

On this website, users also get tools like Update My Location, IP Lookup, Network Lookup, and more.

Final Thoughts:

It is another good online ASN to IP lookup website that also shows the area covered by IP address range over a map.

Pros	Cons
Shows the most active network area over the world map

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Frequently Asked Questions

What is the ASN of an IP?

ASN or Autonomous System Number is a type of unique identifier assigned to an Autonomous System on the Internet. The main purpose of ASN is to route and traffic exchange on the internet. Many other internet infrastructures use ASN for different purposes like BGP Routing, Peering Agreements, Traffic Engineering, etc.

How does ASN work?

Autonomous System Numbers (ASNs) are used in the Border Gateway Protocol (BGP) to facilitate the exchange of routing information between different autonomous systems on the Internet.

What is the range of ASN?

Autonomous System Numbers (ASNs) are 16-bit or 32-bit numbers used to uniquely identify autonomous systems on the Internet. The range of ASNs depends on the bit length used. The adoption of 32-bit ASNs allows for a significantly larger pool of available ASNs, which is necessary to accommodate the increasing number of networks and autonomous systems connected to the Internet.

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